Writing instrument



FIG. 1 is a front elevational view of a pen showing our new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof;

FIG. 7 is a perspective view thereof from the front, top and left side; and,

FIG. 8 is a front elevational view thereof similar to FIG. 1, but showing the cap thereof removed from the pen thereof. 

The ornamental design for a writing instrument, as shown and described. 